Now configure checks for struct sockaddr_storage and the ftp code tries

to survive without it if not found. AIX 4.3 targetted adjustment.

acinclude.m4

@@ -122,6 +122,30 @@ dnl end of non-blocking try-compile test
   fi
 ])
 
+dnl Check for struct sockaddr_storage. Most IPv6-enabled hosts have it, but
+dnl AIX 4.3 is one known exception.
+AC_DEFUN([TYPE_SOCKADDR_STORAGE],
+[
+   AC_CHECK_TYPE([struct sockaddr_storage],
+        AC_DEFINE(HAVE_STRUCT_SOCKADDR_STORAGE, 1,
+                  [if struct sockaddr_storage is defined]), ,
+   [
+#ifdef HAVE_SYS_TYPES_H
+#include <sys/types.h>
+#endif
+#ifdef HAVE_SYS_SOCKET_H
+#include <sys/socket.h>
+#endif
+#ifdef HAVE_NETINET_IN_H
+#include <netinet/in.h>
+#endif
+#ifdef HAVE_ARPA_INET_H
+#include <arpa/inet.h>
+#endif
+   ])
+
+])
+
 dnl Check for socklen_t: historically on BSD it is an int, and in
 dnl POSIX 1g it is a type of its own, but some platforms use different
 dnl types for the argument to getsockopt, getpeername, etc.  So we